This invention relates to a system for the treatment of sludge of the type normally encountered by municipalities and industries. In typical situations, the sludge is developed at waste collection sites to which municipal and industrial waste water of various types is delivered.
Various techniques may be utilized for treatment of waste water including the location of the waste in a settling tank or bed for clarification. The solids portion settles out and the clarified water portion may then be returned to an adjacent stream, river, etc. with or without further treat- ment.
The solids portion, known as sludge, may be transferred to a lagoon or the like, allowed to dehydrate to various levels of moisture content, and then be trucked to a permanent disposal site.
It has been found, however, that an unduly long period of time is often required to reduce the moisture content of the sludge to a level where the partially dehydrated sludge can be efficiently transferred to another location. Thus, where the remaining moisture content is rather high, the expense of shipping to a fill-site or other permanent disposal site can be quite large due to the weight of the moisture. Furthermore, large and often expensive sites may be needed for effective dehydration.
For the above-noted reasons, attempts have been made to achieve removal of liquid content in sludge by utilizing systems other than dehydration lagoons and the like. The efficiency of systems for extracting liquids from sludge, however, must be constantly reviewed in order to determine whether the system costs warrant the expense of operating the system. In other words, those costs must be weighed against the costs of shipping sludge with a high moisture content to a permanent disposal site. Systems for achieving extraction of excess moisture, for example by the use of presses and the like, have not been widely adopted because of such lack of efficiency.